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HIGH-OCCUPANCY VEHICLE _HOV_ LANES I ACHIEVING CURRENT POLICY

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									HIGH-OCCUPANCY VEHICLE (HOV) LANES I:
ACHIEVING CURRENT POLICY OBJECTIVES?
RESPONSES FROM PARSONS BRINCKERHOFF - NOVEMBER 12, 2009




HOV LANES

HAVE HOV LANES SERVED AS AN EFFECTIVE INCENTIVE FOR DRIVERS TO CARPOOL? IF SO,
TO WHAT EXTENT? DID THE INCREASE IN CARPOOLING CORRESPOND TO INCREASED
THROUGHPUT ON THOSE FREEWAYS THAT HAVE HOV LANES? HOW WERE CARPOOLING
AND THROUGHPUT MEASURED?

Various studies both within the State of California and national publications have shown that HOV lanes have been
a positive incentive on carpooling and vanpooling, when compared to corridors without HOV lanes. The impact
relates to increases in average vehicle occupancies that range up to 20% in California (Figure 1). In Los Angeles and
Ventura Counties, the presence of HOV lanes yielded a 77% increase in total carpools as compared to freeways
without HOV lanes (Caltrans, 2009).

There has been a commensurate increase in throughput on the affected freeways. According to the recent 2009
HOV performance report conducted by Caltrans, “HOV facilities carry 34% of the entire freeway’s people in just
20% of the freeway’s space, while an adjacent single mixed-flow lane carries 17% of the entire freeway’s people in
the same 20% space (Caltrans, 2009)”. Carpooling and throughput are measured based on freeway vehicle count
locations, annual surveys of average vehicle occupancies and by occasional user surveying.




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Figure 1: Changes in Average Vehicle Occupancy, Transit Cooperative Research Program Report 95, Chapter 2, 2006.




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HAVE HOV LANES REDUCED CONGESTION IN THE MIXED-FLOW LANES?

In comparison to a no-build condition, HOV lanes have had a positive impact on reducing congestion, both in terms
of raising average vehicle occupancies (AVO) from 1.2 to 1.3 to 1.6, depending on the corridor; and in terms of
overall mobility choices in reducing congestion. The findings from TCRP 95-2 indicate that HOV lanes have an
initial congestion decreasing effect upon the general purpose lanes, but are insufficient for countering long-term
growth trends in travel demand and VMT (TCRP, 2006). As a result, HOV lanes help reduce VMT growth through
higher AVO’s. However, a separate research project conducted for the TRB Task Force for the CMAQ program
indicated that HOV lanes were cost-effective in reducing VMT growth only when coupled with complementary
programs for incentivizing the shift in mode (National Academies of Science, 2002).

HAVE HOV LANES RESULTED IN A REDUCTION IN CRITERIA POLLUTANTS OR GREENHOUSE
GAS EMISSIONS? IF SO, WHAT ACCOUNTS FOR THE REDUCTION?

The Caltrans study of the Los Angeles / Ventura HOV system in 2002 provided detailed findings for typical emission
results. That study indicates, in general, that HOV lanes produce approximately half the emissions per person than
a comparable general purpose lane in the corridor. So, HOV lanes do “reduce” emissions, but only to the extent
compared to a general purpose lane (Los Angeles County MTA, 2002). A Texas Transportation Institute effort
(1997) modeled three different scenarios for a variety of corridors in Texas: no-build, build HOV, build GP.
Altogether, “build HOV” outperformed the other two scenarios for emissions (summarized in TCRP 95-2): “The
HOV lane alternative generated the lowest levels of emissions for hydrocarbons and carbon monoxide, and was
only slightly higher than the 3 GP lane/no HOV lane alternative in nitrogen oxide. The HOV lane option also
resulted in the lowest levels of gasoline consumption among the alternatives. The analysis also indicated that since
increases in demand are expected to continue, the HOV lane alternative may provide even greater benefits
because it provides capacity to serve additional growth while the other alternatives do not (Stockton et al., 1997).”

There has been no recent assessment of GHG (CO2) emissions reduction, or, a comprehensive statewide
assessment for California.

HOT LANES

HAVE HOT LANES REDUCED CONGESTION ON MIXED-FLOW LANES? IN THOSE CASES
WHERE CONGESTION REDUCTION OCCURRED, WERE THE HOT LANES NEW LANES OR THE
CONVERSION OF EXISTING HOV LANES?

For the single corridor in California where HOT lanes have been implemented (I-15), congestion has been reduced
in the mixed flow lanes. Similar results have been reported in many of the other nine HOT lane projects nationally.
Most HOT lanes nationally have been conversions. I-15 was both a conversion of the original reversible flow
project and new lanes for the recently opened extension. Most upcoming HOT lanes in California, including I-10
and I-110 in Los Angeles and I-680 in the Bay Area, will be conversions.




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HAVE HOT LANES ALLOWED FOR INCREASED THROUGHPUT ON THOSE FREEWAYS THAT
HAVE THEM? IN THOSE CASES WHERE INCREASED THROUGHPUT OCCURRED, WERE THE
HOT LANES NEW LANES OR THE CONVERSION OF EXISTING HOV LANES?

A recently produced FHWA Value Pricing Program Lessons Learned report found the following about HOT lane
projects conducted to date (not including I-95 (Miami), I-35W (Minneapolis), or SR-167 (Seattle), as all were too
recent): “The HOV to HOT lane conversions in San Diego, Houston, Minneapolis, and Denver have all been
successful at making better use of previously underutilized HOV lanes, and providing drivers with a congestion-free
alternative. Traffic volumes have increased on the HOT lanes by as much as 140 percent (without loss of speed) to
make use of spare capacity on these lanes. Also, there is some, albeit non-conclusive, evidence HOT lane
conversions have brought relief to adjoining mixed flow lanes by attracting some traffic away from these lanes.
HOT lanes have provided a new high-speed travel option to the public without reduced HOV use. Many users also
view HOT lanes as providing safety due to reduced congestion (FHWA, 2008).”

HAVE HOT LANES RESULTED IN REDUCED CRITERIA POLLUTANTS OR GREENHOUSE GAS
EMISSIONS? IN THOSE CASES WHERE POLLUTION REDUCTIONS HAVE OCCURRED, WERE
THE HOT LANES NEW LANES OR THE CONVERSION OF EXISTING HOV LANES?

Given the very limited experience to date in California, insufficient data exists from which to draw conclusions
regarding overall experience with GHG and pollutants. Hybrid inclusion on HOV lanes has not had a significant
positive (or negative) impact because average travel speeds (50 mph or greater) on the HOV/HOT lanes are above
the speed threshold in which hybrid efficiencies are gained. The Caltrans report for Los Angeles indicated that on
average each HOV facility carries 80 hybrids during both morning and afternoon peak hours (Caltrans, 2009).

Nationally, post-implementation evaluations of HOT lane applications – I-394 in Minnesota, I-15 in San Diego, and,
SR-91 in Orange County – yielded widely varying conclusions regarding the emission impacts of the HOT lanes. In
summary, at worst HOT lanes yield a slight increase in corridor emissions and at best HOT lanes distribute traffic
more efficiently, thereby mitigating overall corridor emissions.

I-394’s adaptation of an existing HOV lane to HOT lane operations showed an overall, corridor increase of Carbon
Monoxide (CO) emissions, the only pollutant of interest in the evaluation. However, this increase was slight (less
than 1% increase), and well within the standards as established by the State of Minnesota (Minnesota DOT, 2006).

I-15’s adaptation similarly revealed an increase in pollutants including CO, Volatile Organic Compounds (VOC),
Nitrous Oxide (NOX), and Particulate Matter less than 10 microns (PM10). However, in comparison to the
evaluation’s control corridor, the I-15 corridor fared much better at mitigating the increase in pollutants.
Comparisons between the general purpose lanes and the express lanes indicates that the Express Lanes’ better
utilization of capacity (as compared to the control corridor) helped absorb growth in traffic and minimized the
increase in pollutants. Researchers concluded that the HOT lane strategy was the only statistically significant
explanation for the mitigation of emissions in the I-15 corridor (San Diego Association of Governments, 2001).

SR-91 involved the construction of four lanes of new capacity. This new capacity’s contribution to emissions far
outweighs the specific effect of HOT operations. However, to control for the addition of new capacity, researchers
evaluated two alternative scenarios, investigating what would have been the impact if the 91 Express Lanes were
(respectively) HOV lanes or general purpose lanes instead. They concluded that HOT lanes have no discernable




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difference from HOV lanes, and, constitute a slight improvement over general purpose lanes for total emissions
(California Polytechnic State University, 2000).

HAVE HOT LANES RESULTED IN INCREASED TRANSIT SERVICE IN CORRIDORS IN WHICH HOT
LANES OPERATE? IF SO, TO WHAT EXTENT? DID THE LEVEL OF TRANSIT SERVICE INCREASE
ABOVE AND BEYOND WHAT WOULD HAVE OCCURRED ABSENT A HOT LANE?

To the extent that transit services were available in the HOT lane corridors and commute choices were expanded
as a result, transit service increased. I-15 in San Diego has seen expanded use of transit service as a result of their
HOT lanes, but revenues from tolling also helped fund expanded transit services for commuters to use (SANDAG,
2001).

HOW MUCH REVENUE IS GENERATED FROM HOT LANES AND HOW IS THE REVENUE BEING
SPENT?

Revenue generation varies for I-15 and SR 91 (which was implemented as a private express toll lane, not HOT lane).
Most HOT lanes essentially cover their operating and maintenance costs, but SR 91 does have a positive cash flow
above operations and maintenance. According to the FHWA Lessons Learned report: “The revenue picture for
HOT lane conversions is generally favorable. In all but one of the HOT lane conversions, revenues have been
sufficient to support operating expenses, although in the case of the I-394 HOT lanes in Minneapolis it took over a
year until revenues exceeded operating expenses. One project, the I-15 HOT lanes in San Diego, is subsidizing
transit service with toll revenue in addition to paying for HOT lane operating expenses (support for and emphasis
on transit also is important at PANYNJ and will be integral to new managed lanes in Houston). One smaller
program (Houston) did not raise sufficient revenue to cover all operations and a long-standing program (San Diego
I-15) is starting new fees to cope with declining use and revenues due to the opening of a new nearby facility.
Covering the initial capital cost of conversion from HOV to HOT lane operation is more difficult, especially where
conversion requires expensive capital outlays, or where a relatively large number of vehicles are allowed to travel
free (FHWA, 2008).”

HOW HAVE HOT LANES IMPACTED LOWER-INCOME DRIVERS?

Based on user surveys on SR 91 and I-15, there has been no negative impact, and, use is drawn from all socio-
economic sectors (CalPoly 2000, SANDAG 2001). Toll policies can influence a positive finding for income equity. As
an example, Los Angeles Metro will test a credit program for those who take transit, allowing for a positive impact
to drivers who regularly take transit on the HOT corridor.

Besides the use of facilities by various demographic groups, analysis of the customer markets for HOT lanes are
often lacking in discussion. On I-15, for example, 38 of 43 census tracts that comprise the majority of corridor
customers have median household incomes greatly in excess of San Diego MSA median income (in some cases,
upwards of $50,000 or more greater than the MSA median. So, the average income of HOT lane users is higher
than a regional average because the average of I-15 corridor users are likewise higher than the regional average.




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Figure 2: Median Household Income by Census Tract, U.S. Census Bureau, 2000.




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HOW ARE, OR COULD, THE IMPACTS ON LOWER-INCOME DRIVERS BE MITIGATED?

Los Angeles County Metro is experimenting with a credit program tying transit use to toll tag accounts, which in
turn will permit lower income drivers to take the HOT lane for free if they regularly ride transit. Additionally, the
Metropolitan Transportation Commission developed a policy alternative for congestion pricing on the Bay Bridge in
the mid 1990s that involved “Lifeline Tolling”, linking discounted toll rates to those eligible for utility assistance.
The same policy concept could be extended for HOT lanes. However, most equity analyses shows that provided
free use of HOT lanes by carpools is continued, no need for mitigation is required as multiple modes of travel can
enjoy the travel time benefits without additional cost to the user.

REFERENCES

Caltrans District 7. 2008 HOV Annual Report, January 2009,
http://www.dot.ca.gov/dist07/resources/hov/docs/2008%20HOV%20ANNUAL%20REPORT.pdf

Transit Cooperative Research Program (TCRP). Traveler Response to Transportation System Changes: HOV
Facilities, TCRP Report 95, Chapter 2, Transportation Research Board, 2006,
http://onlinepubs.trb.org/Onlinepubs/tcrp/tcrp_rpt_95c2.pdf

National Academies of Science. The Congestion Mitigation and Air Quality Improvement Program: Assessing 10
Years of Experience, Special Report 264, 2002, http://www.nap.edu/catalog.php?record_id=10350

Los Angeles County Metropolitan Transportation Authority. HOV Performance Program Evaluation Report,
November 2002, http://www.metro.net/projects_studies/hov/images/hov_final_evaluation_report.pdf

B. Stockton, G. Daniels, K. Hall, and D. Christensen. An Evaluation of High-Occupancy Vehicle Lanes in Texas, 1996,
Texas Transportation Institute, 1997, http://tti.tamu.edu/documents/1353-6.pdf

Federal Highway Administration. Value Pricing Pilot Program: Lessons Learned, August 2008,
http://ops.fhwa.dot.gov/publications/fhwahop08023/vppp_lessonslearned.pdf

Minnesota Department of Transportation. MnPass Technical Evaluation Final Report, November 2006,
http://www.mnpass.org/pdfs/394mnpass_tech_eval.pdf

San Diego Association of Governments. I-15 Congestion Pricing Project: Phase II Year Three Overall Report,
September 2001,
http://ops.fhwa.dot.gov/tolling_pricing/value_pricing/pubs_reports/projectreports/pdfs/interst15_congestion.pdf

California Polytechnic State University. Continuation Study to Evaluate the Impacts of the SR-91 Value Priced
Express Lanes: Final Report, December 2000,
http://ops.fhwa.dot.gov/tolling_pricing/value_pricing/pubs_reports/projectreports/pdfs/sr91_expresslanes.pdf




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